Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757720AbZAGNDe (ORCPT ); Wed, 7 Jan 2009 08:03:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757264AbZAGNDE (ORCPT ); Wed, 7 Jan 2009 08:03:04 -0500 Received: from intermatrixgroup.ru ([195.178.208.66]:34170 "EHLO tservice.net.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756919AbZAGNDB (ORCPT ); Wed, 7 Jan 2009 08:03:01 -0500 Date: Wed, 7 Jan 2009 16:02:59 +0300 From: Evgeniy Polyakov To: Herbert Xu Cc: Willy Tarreau , Jens Axboe , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Jarek Poplawski Subject: Re: Data corruption issue with splice() on 2.6.27.10 Message-ID: <20090107130259.GB32336@ioremap.net> References: <20090107115032.GA25198@gondor.apana.org.au> <20090107115605.GA29250@ioremap.net> <20090107115921.GA25323@gondor.apana.org.au> <20090107121530.GA30164@ioremap.net> <20090107122238.GB25673@gondor.apana.org.au> <20090107123741.GA31255@ioremap.net> <20090107124246.GA26034@gondor.apana.org.au> <20090107124629.GA31732@ioremap.net> <20090107125535.GC6307@1wt.eu> <20090107125734.GA26331@gondor.apana.org.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090107125734.GA26331@gondor.apana.org.au> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1158 Lines: 27 On Wed, Jan 07, 2009 at 11:57:34PM +1100, Herbert Xu (herbert@gondor.apana.org.au) wrote: > On Wed, Jan 07, 2009 at 01:55:35PM +0100, Willy Tarreau wrote: > > > > kernel is 2.6.27.10 + a few patches (squashfs, etc..., nothing related to > > 2.6.27 will enable GSO by default if SG is enabled at registration > time. So even if later sg was turned off without gso being turned off, it will try doing fair page transfer and not falling back to the copy. The simplest case is to also turn gso off, but with older ethtools it is not possible and you hit the bug. If I understood correctly Jarek's patch, he wants to allocate a page and copy linear content of the skb there, so this will end up being the same case as with splicing from the file. And while generally this may be a good idea, but with usual 1.5k mtu this will copy every skb, which is rather bad idea. Will have to think :) -- Evgeniy Polyakov -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/